Coherentism and Memory

One of the most common features of most theories of knowledge is that our beliefs must have some justification to count as knowledge. To explore why want justification let us as part of our theory of knowledge let us consider the Justified True Belief (JTB) theory of knowledge which states for a person S to know proposition P:

• P must be true
• S must believe P
• S must have justification for their belief in P

Without this final criteria: S must have justification for their belief in P; it would be possible for a person just to believe a random set of propositions and any that turned out to be true by coincidence would count as knowledge. This seems rather odd because it allows people to know things by luck. So instead we want a person to have some kind of justification for their beliefs even if those beliefs are true.

However, the JTB definition doesn’t give us any guidance as to what it means to justify our belief. Initially one might argue that if I have a justification for a belief I can produce some kind of formal proof e.g. I can derive it from the laws of logic and I can produce that derivation if asked. Yet this seems to mean the only statements we can justify are ones related to Logic or Mathematics. However, we often talk about knowing basic statements “I know there is a chair over there”. So perhaps we should look for some kind of empirical justification.

We might be tempted to argue that it is justified if I can produce some sort of empirical evidence for it. For example in the case of the chair my justification might be that I can see the chair in the corner. But how do we know we know our senses are reliable? Maybe I’m dreaming or hallucinating? This leads us to the problem of not being able to trust empirical justification.

Coherentism is a theory that helps us fill in the blanks with respect to justification. It argues we all have sets of beliefs 1 that whether or not a belief is justified/counts as knowledge depends on how well it fits with our other beliefs. For example, my belief there is a table in the kitchen is supported by my belief that my eyes are reliable; my belief my friend told me there is a table in the kitchen and my belief when I put my plate on what I thought was a table last night my food didn’t fall to the fall. Since these beliefs all fit with my belief the table is there they can support each other.

Coherentism also allows for beliefs to count against each other 2. For example, my belief that the earth is flat is contradicted by my belief that people I respect have told me they have travelled all the way around it as well as my belief that I’ve seen photos from space that seem to show the Earth is round. In this case my belief that earth is flat does not cohere with my other beliefs so it should not count as knowledge.

Generally, Coherentism is considered at a particular point in time, for example, Person A holds beliefs 1,2 and 3 right now in time and we try to work out to what extent they cohere. However, our beliefs persist through time, in fact we often lose some beliefs and gain others (either subconsciously) over time. For instance, when I get back from work I have the belief I have put my keys in my draw, yet by the next morning I have often lost this belief.

We commonly called the faculty that persists at least some of our beliefs from one time to another memory. And some philosophers argue that it is capable of generating knowledge. In her paper “Memory as a Generative Epistemic Source” Jennifer Lackey argues against what she calls the Preservation View of Memory (PVM). This is the view that memory is only capable of transferring knowledge from point in time to another point in time and is not able to create knowledge and she gives the following formulation:

Person A only knows belief B at time T2 if A knew B at T1 (where T1 is some time before T2) and if A acquired B at T1 though some source other than memory.

A crude summary of Lackey’s argument is then that if a person at T1 acquires belief B but does not know it because they have a defeater d (a defeater is something that undermines a person’s belief); then at a later time T2 they have lost defeater d, at this point this would allow B to count as knowledge. And in this sense the person has acquired new knowledge by memory.

Lackey’s argument relies on the idea that memory does not perfectly transmit our beliefs from one time to another; instead, it transmits a subset of our beliefs 3. This idea can also be applied to coherentism. If at time A, I have a set of beliefs that do not cohere; then I lose some of my beliefs so by the point at time B my beliefs cohere I will now have acquired some new knowledge but the only thing that has happened is that I have had by beliefs transmitted through time by my memory.

To illustrate this let’s consider an example. One day I hold the following beliefs: Dave told me he is a policeman; Dave is a liar and Dave is a policeman. Since these do not cohere well I do not count the belief Dave is a policeman as knowledge. Then some years later I forget that Dave is a liar. At this point I have the beliefs: Dave told me he is a policeman and Dave is a policeman. At this point, these two beliefs fit together rather well so I know Dave is a policeman and hence I have acquired new knowledge via my memory.

Overall, this demonstrates that under coherentism we can acquire new knowledge via our memory so long as that our memory is not perfect. However, there do remain some open questions in particular in waits to be seen how this can fit in with the idea of considering coherentism at a societal level.